Open-hearth regenerative furnace



Dec. '16, 1930. J. o. GRIGGS 1,785,549

OPEN HEARTH REGENERATIVE FURNAGE Filed April l. 192.9

Patented Dec. 16, 1930 UNITED STATES JOHN o. GRIGGS, or STEUBENVILLE,oHIo OPEN-HEARTH REGENERATIVE FURNACE Application iilea April 1, 1929.serial No. 351,490.

ciency and reduced melting time, and which reduces construction costs,as compared with prior regenerative open hearth furnaces.

The preferred embodiment of the invention is shown in the accompanyingdrawings in which F ig. l is a section taken longitudinally of one endof the furnace; and Fig. 2

is a horizontal section taken on line II--II,`

Fig. 1.

This invention is applicable to open hearth regenerative furnaces whichare provided at each end with a horizontally disposed gas port, an airport above the gas port, and passages for conducting gas and air to therespective ports, these passages usually leading from gas and air slagpockets. In accordance with the invention, each end is provided with aby-pass conduit leading from the air supply to the bottom of the gasport anterior of its outlet to the furnace, and the bottom of the gasport adjacent to but anterior of the outlet of the by-pass conduit isprovided with an upwardly extending baffle. This construction gives atype of Venturi action, as a result of which there is' produced auniform flow of air from the bypass conduit, the flow of gas regulatesthe flow of'air, and thorough mixing and highly efficient combustionresult.

In the drawings, there is shown one end of a conventional open hearthregenerative furnace comprising a hearth l, end wall 2, roof 3, and gasand air slag pockets 4 and 5 respectively, connected to regeneratorchambers containing checkerwork, not shown, and

it will be understood that the construction of the opposite end of thefurnace is similar to that shown and described here. An uptake 6conducts gas from slag pocket 4 to a i gas port 7 whose outletcommunicates with the furnace, and air is passed from slag pocket 5through uptake 8 to an air port 9 above the gas port. The gas and airports are separatedby an arch 10 extending forwardly from end wall 2,and the arch may be water-cooled in any suitable manner. Air from s'lagpocket 5 is also passed to the gas port through a by-pass conduitl1,\and, in accordance with the invention, this by-` pass opens into thebottom of the gas portl at a point anterior of its outlet to thefurnace. The bottom of the gas port adjacent the outlet of, butanteriorto, the by-pass conduit is iprovided with an upwardly extendingba e. This construction is preferably accomplished in the manner shownin Fig. 1 by extending the gas port bottom 12 between uptake 6 andby-pass l1, above the plane of the bottom 13 of the forward portion ofthe gas port. The outlets of uptake 6 and by-pass 11 being disposed inthe bottom of the gas port, the outlet of the by-pass is in a planeparallel to but below that of uptake 6, and in this mannerthere isprovided anozzle passage similar to a Venturi tube, the partition Wallforming the throat. In the use of furnaces having burners con.- structedin accordance with the invention, the static head of gas from the rearportion of the gas port is converted to a velocity so head as the gasflows through the throat portion. Suction is thus created in the airby-pass conduit, and by virtue of this Venturi v nozzle action, the flowof air to the gas port is proportioned by that of the gas, makingregulation of the flame at different stages of the melt readilypossible, and preventing back flow of gas into the by-pass conduit. Inthe forward portion of the gas port the gas again assumes a static head,alld this enlarged portion also takes care of any increase in gas volumedue to combustion.

In prior furnaces which are commercially practical, air for combustionis taken from the air port above the gas port, and because this air iscooled by infiltration through the walls and roof, the flame temperatureis lowered. Furthermore, there is an inadequate mixture of the air withthe gas, resulting in incomplete combustion and in a longer flame thandesirable for high eiciency. With the construction provided by thisinvention, the draft created in by-pass conduit 11 supplies asubstantial proportion of air at an initially high temperature, and a.smaller proportion of air cooled by infiltration than in prior furnaces.This, together with the very lthorough mixing caused by the nozzleaction, cmbines to give a higher flame temperature than in priorfurnaces; y

The thorough mixing of gas With highly heated air givessubstantiallycomplete combustion in the vicinity of the gas port outlet, so that thefurnace operates With a short flame, reducing cutting out of thebrickwork at the opposite end of the furnace. Likewise, because of theproduction of a hotter flame than heretofore, the melting time isdecreased, and this with more eicient combustion, reduces fuelconsumption and operating costs. Also, the invention provides a simpleand inexpensive construction at the burner ends of the furnaces. l

According to the rovisions of the Patent Statutes, I have eXp ained theprinciple and mode o'f operation o f my invention, and have describedwhat I now consider to represent its best embodiment. However, I desireto have it understood that, Within the scope of the appended claim theinvention may be practiced otherwise than as specifically described.

I claim as my invention:

An open hearth regenerative furnace provided at each end With ahorizontally disposed gas port, an air port above the gas port, passagesfor conducting gas and air to said ports, and a by-pass conduit leadingfrom said air passage to the bottom of said gas port at a point anteriorof its outlet, the bottom of said gasort adjacent to but anterior of theoutlet o said by-pass being provided With an upwardly extending baiileto.

cause uniform How of air from the by-pass into the gas port.

In testimony whereofI sign my name.

J PDT O. GRIGGS.

